hrvatski

ODGOVOR NA SOLNI I OSMOTSKI STRES U UROČNJAKA (Arabidopsis thaliana (L.) Heynh.) S PROMIJENJENOM EKSPRESIJOM PROTEINA BPM I DMS3

BPM proteins from the MATH-BTB family are part of the ubiquitin-proteasomal pathway (UPS) - a regulatory mechanism that enables the selective degradation of proteins in the cell [1]. Recent research suggests that BPM proteins are involved in RNA-directed DNA methylation (RdDM) through direct interaction with DMS3 protein [2]. Both mechanisms, UPS and RdDM, are important for developmental processes, but also for the adaptation of plant growth and development in changing environmental conditions [3, 4]. The aim of this study was to investigate the effect of salt and osmotic stress in Arabidopsis thaliana seedlings with modified expression of the functional proteins BPM and DMS3. Seedlings with overexpressed BPM1 gene (oeBPM1 ), downregulated BPM1, 4, 5 and 6 genes (amiR-bpm ), overexpressed DMS3 gene (oeDMS3 ), nonfunctional DMS3 protein (dms3-1 ), or wild type seedlings were used for the study. Stress indicators were photosynthetic efficiency (PIabs), proline content, level of lipid peroxidation expressed as MDA content, and activity of two antioxidant enzymes – ascorbate peroxidase (APX) and catalase (CAT). To induce salt or osmotic stress, seedlings were cultured from day 5 to day 12 on medium containing 75 mmol dm-3 NaCl and 150 mmol dm-3 mannitol, respectively. When comparing control seedlings and seedlings treated with NaCl or mannitol, oeBPM1 line proved to be more sensitive to mannitol treatment, which caused an increase in proline content, MDA and CAT activity, and decrease in PIabs. On the other hand, amiR-bpm line showed higher sensitivity to salinity, with increased CAT activity and a decrease in MDA, APX, and PIabs parameters. In oeDMS3 line, both treatments resulted in proline accumulation and a decrease in PIabs. However, no difference was observed in MDA content, and activities of APX and CAT compared to the control. Seedlings of dms3-1 line showed greatest accumulation of proline and MDA after mannitol treatment. Increased activity of APX and CAT was observed after NaCl treatment but not after mannitol treatment. Both treatments caused a decrease in PIabs compared with control. The differences in stress response in oeBPM1 and amiR-bpm lines suggest a possible specific role of individual BPM proteins in the response to salt and osmotic stress. In addition, the results suggest that DMS3 protein has a role in the tolerance of salt and osmotic stress in thale cress.

MATH-BTB, UPS, RdDM, indikatori stresa

nije evidentirano

engleski

SALT AND OSMOTIC STRESS RESPONSE IN THALE CRESS (Arabidopsis thaliana (L.) Heynh.) WITH MODIFIED EXPRESSION OF BPM AND DMS3 PROTEINS

BPM proteins from the MATH-BTB family are part of the ubiquitin-proteasomal pathway (UPS) - a regulatory mechanism that enables the selective degradation of proteins in the cell [1]. Recent research suggests that BPM proteins are involved in RNA-directed DNA methylation (RdDM) through direct interaction with DMS3 protein [2]. Both mechanisms, UPS and RdDM, are important for developmental processes, but also for the adaptation of plant growth and development in changing environmental conditions [3, 4]. The aim of this study was to investigate the effect of salt and osmotic stress in Arabidopsis thaliana seedlings with modified expression of the functional proteins BPM and DMS3. Seedlings with overexpressed BPM1 gene (oeBPM1 ), downregulated BPM1, 4, 5 and 6 genes (amiR-bpm ), overexpressed DMS3 gene (oeDMS3 ), nonfunctional DMS3 protein (dms3-1 ), or wild type seedlings were used for the study. Stress indicators were photosynthetic efficiency (PIabs), proline content, level of lipid peroxidation expressed as MDA content, and activity of two antioxidant enzymes – ascorbate peroxidase (APX) and catalase (CAT). To induce salt or osmotic stress, seedlings were cultured from day 5 to day 12 on medium containing 75 mmol dm-3 NaCl and 150 mmol dm-3 mannitol, respectively. When comparing control seedlings and seedlings treated with NaCl or mannitol, oeBPM1 line proved to be more sensitive to mannitol treatment, which caused an increase in proline content, MDA and CAT activity, and decrease in PIabs. On the other hand, amiR-bpm line showed higher sensitivity to salinity, with increased CAT activity and a decrease in MDA, APX, and PIabs parameters. In oeDMS3 line, both treatments resulted in proline accumulation and a decrease in PIabs. However, no difference was observed in MDA content, and activities of APX and CAT compared to the control. Seedlings of dms3-1 line showed greatest accumulation of proline and MDA after mannitol treatment. Increased activity of APX and CAT was observed after NaCl treatment but not after mannitol treatment. Both treatments caused a decrease in PIabs compared with control. The differences in stress response in oeBPM1 and amiR-bpm lines suggest a possible specific role of individual BPM proteins in the response to salt and osmotic stress. In addition, the results suggest that DMS3 protein has a role in the tolerance of salt and osmotic stress in thale cress.

MATH-BTB, UPS, RdDM, stress indicators

nije evidentirano